oh hey i am now getting something similar with gemini-2.5-flash-image (nanobanana) - this just happened:
Trying to contact the model returned this error: { "error": { "code": 404, "message": "models/gemini-2.5-flash-image-preview is not found for API version v1beta, or is not supported for generateContent. Call ListModels to see the list of available models and their supported methods.", "status": "NOT_FOUND" } }
all my other gemini flash models appear to be working 
edit: ok i fixed it. the url of some of the gemini image models have changed and needed to be updated in URL of the service hosting the model field
for the embedding model it should be https://generativelanguage.googleapis.com/v1beta/models/gemini-embedding-001:embedContent